Over the years, it has become essential that firearms, like many other devices, be capable of convenient and discrete transport. Although handguns are fairly easy to store and transport in compact carrying cases, it is not as easy to do so with rifles with longer barrels.
Therefore, some rifles have been manufactured with barrels that can be disassembled, i.e., modular rifles, so that smaller carrying cases could be utilized to transport the same. A modular rifle typically includes a lower receiver assembly, an upper receiver assembly, a barrel and a coupling mechanism for coupling the barrel to the upper receiver assembly. The M-16 style rifle is a type of modular rifle system commonly used by military and law enforcement that features a gas-operated bolt and bolt carrier system, as disclosed, for example, in U.S. Pat. No. 2,951,424, issued to Eugene M. Stoner on Sep. 6, 1960 (incorporated herein by reference in its entirety). The AR-15 style rifle is a similarly designed modular rifle system commonly sold and used in civilian applications.
For most M-16/AR-15 style rifle systems, the barrel is assembled by connecting the barrel to the upper receiver utilizing a barrel nut through threaded engagement. The barrel nut must be appropriately torqued to properly align the barrel and completely tighten the barrel nut, typically requiring the use of specialized tools and a bench vise. Consequently, the barrel cannot be quickly or easily removed, changed, or assembled in the field under combat conditions or exigent circumstances, and the rifle system cannot be quickly and easily stored in a disassembled state.
In response to the problems associated with the traditional threaded engagement of the barrel and upper receiver, various devices and mechanisms that do not require tools for assembly and disassembly have been introduced in the market. A popular alternative is a tool-free retrofitted coupling mechanism meant to reduce time to assemble and disassemble the rifle. However, even though they are tool-free, the coupling mechanisms in the prior art pose several disadvantages.
First, it is difficult to accomplish a secure fit when assembled. Not only is a secure fit critical to the rifle's proper function but a non-secure fit is a major safety hazard.
Second, the inside of the barrel could be exposed to dust and debris because the coupling mechanisms of the prior art are not completely sealed when in use. Again, this could be detrimental to the proper function of the rifle as well as to the safety of the user.
Third, the coupling mechanisms of the prior art often times require additional fabrication on the existing barrel and upper receiver, for example, fabrication or modification of existing threads. Hence, the user may not be able to install the coupling mechanism himself and additional costs for installation might be required.
Therefore, a need exists for a coupling mechanism that can be easily installed, and for quickly and easily attaching and detaching a barrel of a firearm while providing a secure attachment during use.